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  1. ZooKeeper
  2. ZOOKEEPER-544

improve client testability - allow test client to access connected server location


    • Type: Improvement
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 3.3.0
    • Component/s: c client, java client, tests
    • Labels:
    • Hadoop Flags:


      This came up recently on the user list. If you are developing tests for your zk client you need to be able to access the server that your
      session is currently connected to. The reason is that your test needs to know which server in the quorum to shutdown in order to
      verify you are handling failover correctly. Similar for session expiration testing.

      however we should be careful, we prefer not to expose this to all clients, this is an implementation detail that we typically
      want to hide.

      also we should provide this in both the c and java clients

      I suspect we should add a protected method on ZooKeeper. This will make a higher bar (user will have to subclass) for
      the user to access this method. In tests it's fine, typically you want a "TestableZooKeeper" class anyway. In c we unfortunately
      have less options, we can just rely on docs for now.

      In both cases (c/java) we need to be very very clear in the docs that this is for testing only and to clearly define semantics.

      We should add the following at the same time:

      toString() method to ZooKeeper which includes server ip/port, client port, any other information deemed useful (connection stats like send/recv?)

      the java ZooKeeper is missing "deterministic connection order" that the c client has. this is also useful for testing. again, protected and
      clear docs that this is for testing purposes only!

      Any other things we should expose?


        1. ZOOKEEPER-544.patch
          12 kB
          Patrick Hunt
        2. ZOOKEEPER-544.patch
          11 kB
          Mahadev konar
        3. ZOOKEEPER-544.patch
          11 kB
          Mahadev konar



            • Assignee:
              phunt Patrick Hunt
              phunt Patrick Hunt
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